System and method to minimize laser misalignment error in a firearms training simulator

ABSTRACT

A weapon simulation system is used to correct the misalignment between a laser of a simulated weapon and an aim point of the simulated weapon. A compensation offset profile and a compensation angle profile are stored in a weapon controller card in the simulated weapon identifying the misalignment of the laser module in the corresponding simulated weapon. The compensation offset profile and compensation angle profile is transmitted from the weapon controller card to a central computer, where the central computer calculates the aim point of the simulated weapon using said compensation offset profile and said compensation angle profile from said weapon controller card. The position of the simulated weapon with respect to a screen of the weapon simulation system is further calculated using an RFID reader in electrical communication with the weapon controller card and at least one RFID tag positioned in a fire line mat, which transmits the position information to said central computer.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/753,974, filed on May 25, 2007, which claims priority from provisional patent application 60/803,307, filed on May 26, 2006, each application being relied upon and incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to weapon simulation systems having a sight, and, more particularly, to weapon simulation systems having a sight with a laser to calculate the correct orientation of a simulated weapon.

BACKGROUND OF THE INVENTION

Firearms training simulators train police and military personnel with the proper use and handling of weapons without using real firearms and their associated ammunition. The firearms simulator is designed for indoor training in a safe environment, and uses infrared laser modules housed in the barrel of a simulated weapon as a means to determine where the weapon is pointing on a two-dimensional screen. The distance between the student and the screen is very short relative to real world distances since the simulation is done in a typical interior room. In particular, firing line distances of twenty feet are not uncommon for a screen that may span thirty feet wide.

Students use the day or optical sight of the simulated weapon to aim the firearm. In the real world, a process called boresighting, which involves mechanically adjusting a weapon's sight, is used to ensure that the sight of the simulated weapon is calibrated correctly to the shooter. With boresighting, the barrel is aimed at a point of reference, and is confirmed by an optical reference. This may be achieved by using the eye to look through the barrel, or by placing a suitable light source (e.g., a laser) into the barrel. The sight is then aligned to the same point of reference. Thus, once the firearm is boresighted, the sight can be “zeroed” by firing live rounds.

For a weapon simulator, there is no projectile to verify the accuracy of boresighting as with actual weapons. Consequently, an electronic boresight is used to determine the offset necessary to determine the relationship between the laser impact and line of sight. Ideally, this electronic boresight should be able to define the relationship without respect to where the student is aiming on the screen. However, if there is any misalignment of the laser relative to the sight, then the only correct point is at the point of boresight and everywhere else would be incorrect.

An example of this problem of misalignment in the horizontal direction (X) is illustrated in FIG. 1, wherein a simulated weapon 10 is aimed at a screen 12 bearing the system targets. The simulated weapon 10 is shown in two positions 10A, 10B having a corresponding aim point line 14A, 14B (the aim point line 14A, 14B may be any reference aiming line, such as the sight aim point (a line of sight) or barrel aim point), but the laser is projected along laser line 16A, 16B. The simulated weapon 10A is shown at the position at boresight. In order for the simulator to accurately determine the relationship between the line of sight or the aim point line 14 and the laser impact or laser line 16 over the entire screen 12, certain factors must be known. These factors include the amount of misalignment between the laser path 16 and line of sight 14. Because of the configuration of the room surrounding the weapon simulator 10, any error caused by misalignment is amplified across the horizontal span of the screen 12. That is, the projected length 18A, 18B into the plane of the screen 12 between the line of sight or aim point 14 and laser impact 16 changes significantly with changing position and orientation between the simulated weapon 10 and the screen 12 as shown in a comparison of the positions of weapon simulator 10A and weapon simulator 10B in FIGS. 1 and 2. The distance between the aim point line 14A and the actual laser line 16A of the first weapon position 10A is the error distance 18A, and the distance between the aim point line 14B and the actual laser line 16B of a second weapon 10B is the error distance 18B. Clearly the second error distance 18B is much greater than the first error distance 18A due to the orientation and position of each weapon position 10A, 10B, such that a single measurement for correction of the alignment error in the weapon 10A, 10B at different locations will not properly work. Further, the occasional overlap in the error distances 18A, 18B, as shown in FIG. 2, make it difficult for a central computer 15 of the weapon simulation system to ignore and compensate for this error since the misalignment could be large and unpredictable because the origination of the laser path 16A, 16B from corresponding weapon simulator 10A or 10B is not known. The same type of misalignment errors occur in the vertical direction (Y) as well.

One partial solution is to mechanically align the laser line 16 with the line of sight 14 in the horizontal direction (X). However, because of tolerances in both the simulated weapon 10 and the measurement fixture, a repeatable perfect alignment of the laser line 16 may not be cost effective in a production environment. In addition, the mechanical alignment would not compensate any misalignment in the vertical direction (Y) since the aim point requires a clear path of any obstructions, such as the laser module, and readjustment would be necessary every time a new type of sight is used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view illustration of different aim points of simulated weapons on a target or screen at different positions;

FIG. 2 is a top view illustration of different aim points of simulated weapons on the target or screen at different positions as illustrated in FIG. 1, with the weapons starting at different positions;

FIG. 3 is a top view illustration from FIG. 1 showing a first error reduction due to misalignment using ELPM;

FIG. 4 is a top view illustration from FIG. 1 showing a second error reduction due to misalignment using ELPM and LCSPS;

FIG. 4 a is a top view illustration from FIG. 4 showing an enlarged view of a simulated weapon illustrating offset and angle misalignment in the horizontal direction;

FIG. 5 is an illustration of a simulated weapon user on a student positioning system; and

FIG. 6 is an illustration of a simulated weapon having components for error correction illustrating offset and angle misalignment in the vertical direction.

DESCRIPTION OF THE INVENTION

A weapon simulation system and method to minimize laser misalignment error in a firearms training simulator addresses the problems in error correction found in conventional weapons simulators, providing a more accurate and cost effective solution to correcting the errors, is illustrated in the attached drawings. The weapon simulation system 8 includes a simulated weapon 10 having a weapon controller card 24 that is in electrical communication with a central computer 15, with the central computer creating and controlling the simulation scenario broadcast on a screen 12. The simulated weapon 10 includes a laser module 29 that generates a laser line 16 to be directed at a simulated target generated by the central computer 15 on the screen 12. Furthermore, the central computer 15 will monitor when the simulated weapon 10 has been fired and control scenarios surrounding operation of the simulated weapon 10 (such as when the simulated weapon experiences a simulated malfunction). Further, although the system 8 is described with the use of one simulated weapon 10, it is clear that multiple simulated weapons 10 may be used in the system 8 with the laser misalignment error being eliminated in each weapon 10 as described herein.

Referring to FIGS. 3-6, accuracy of the measurement of the laser line 16 location on the screen 12 is improved through the use of an electronic laser profiling system or method (referred to as “ELPS” or “ELPM”) 20 in a simulated weapon 10 (see FIG. 6) and a low-cost student positioning system (or “LCSPS”) 22 in the environment surrounding the simulated weapon 10 (see FIG. 5). More specifically, the ELPS 20 can be used alone, as illustrated in FIG. 3, depending on the amount of error 21 that can be tolerated in a particular weapon simulation system 8. That is, if the central computer 15 assumes that the simulated weapon 10 is in a particular predetermined location in the X, Y, and Z directions at all times (as shown as 10A), even when the simulated weapon 10 is moved from that location (as shown as 10B), the error 21 is determined by having the central computer 15 extrapolate an assumed laser line 16C generated from simulated 10A rather than simulated weapon 10B to calculate an assumed aim point line 14C. The error 21 is the difference between the assumed aim point line 14C and the actual aim point line 14B. Alternatively, both the ELPS 20 and LCSPS 22 may be employed to allow for the use of compensation offsets D, D2 and angles θ, θ2 profiles relative to a known reference plane P that are stored in each simulated weapon 10 for each of its sights/optics to determine the error that is needed to be corrected (see FIG. 4), and the aim point 17B is precisely located on the screen 12 according to the actual aim line 14B, analogous to aim point 17A being precisely located on the screen 12 according to the actual aim line 14B since it is at the boresight position.

Referring to FIG. 6, the ELPS 20 incorporates the use of a weapon controller card 24 in the simulated weapon 10. The weapon controller card 24 includes a microprocessor/microcontroller having an electronic memory that will store information characterizing the alignment of a laser path 16 (emitted by laser module 29) relative to the sights 27 affixed to the simulated weapon 10. The weapon controller card 24 is connected with any sensors mounted in or affixed to the simulated weapon 10, and handles communication between the sensors and a central computer 15. More specifically, the actual positions of the laser impact 16 are noted for the sight 27, typically at the time when the simulated weapon 10 is being manufactured. The horizontal and vertical offsets D, D2 between the sight 27 and the laser path 16 as well as the horizontal and vertical angles θ, θ2 between the aim point 14 and laser line 16 are measured for each sight 27 relative to a known reference plane P in order to ensure that the laser line 16 will match the line of sight 14 at the specified firing line distance 19. This data is then stored in the weapon controller card 24, which is housed in the simulated weapon 10. Because this information is electronically stored in the simulated weapon 10 itself, there are no moving parts that can cause the information to be incorrect (unlike mechanically corrected alignment between the laser beam from laser module 29 and sights 27), and it guarantees that any variations among designs of simulated weapon 10 will be consistent and minimized.

The weapon controller card 24 stores this profile data (including compensation offset profiles and compensation angle profiles) electronically in the simulated weapon 10 to provide the adjustment information to the central computer 15 for the weapon simulation system 8. The ELPS 20 uses the offsets D, D2 from the aim point 14 of the simulated weapon 10 as a comparison to the actual laser hit 16 at the firing line distance 19 and the angles θ, θ2 between the aim point lines 14A, 14B and the laser lines 16A, 16B relative to the sights 27. The ELPS 20 will allow the central computer 15 of the weapon simulator 10 to calculate the correct offset for any path in which the laser path 16 will follow at distances different from the boresighted point to allow the weapon simulator 10 to correct any misalignment of the laser path 16 if the position of the weapon simulator 10 is known (that is, the position of the simulated weapon from the target on the screen 12).

Using the ELPS 20, the boresighting of the laser path 16 can be more exact, consistent, and robust, unlike a mechanical adjustment that will always have some tolerance stack up and human error, and will further be subjected to mechanical damage. Once the simulated weapon 10 is registered on the weapon controller card 24, the particular electronic laser profile will be downloaded to the central computer 15 of the weapon simulation system 8 so that the central computer 15 can adjust the laser position 16 electronically to compensate for any misalignment or error distance 18A, 18B due to mechanical tolerances in the manufacturing process.

Once the offsets D, D2 and the departing angles θ, θ2 of the laser beam 16 relative to the line of sight 14 are known from the weapon controller card 24, the next step is to determine the originating position of laser on the weapon simulator 10 using the LCSPS 22. Since the firing line 16A, 16B is a known or assumed distance 16 from the screen 12 (in the Z-direction), the unknowns are that are needed to truly determine the student's aim point in the simplified two-dimensional illustration are the horizontal position (or X-direction) and the vertical position (or Y-direction). However, in order to realize this method into three-dimensional space, the cant of the simulated weapon 10 is a factor and must be included in the calculations to determine the actual aim point. Consequently, a cant sensor 31 is included in the weapon simulator 10 to determine the cant angle of the simulated weapon 10 and transmit the corresponding information to the weapon controller card 24, which is in electrical communication with the central computer 15 to factor in the cant angle in determining the position of the weapon controller card 24. The cant sensor 31 is needed because there is a physical offset between the laser module 29 and the aim point line 14, and the cant angle occurs when the student does not hold the simulated weapon 10 in a substantially vertical position.

The LCSPS 22 can determine the unknown X- and Y-positions of the simulated weapon 10 through the use of Radio Frequency Identification (or “RFID”). RFID technology is designed to be a very low cost means for product identification and tracking, and has been adopted by the military and retail sector as a “smart” alternative way of bar coding products for specific identification. More specifically, the RFID system uses RFID tags 26 and an RFID reader 28 to monitor an item. Referring to FIG. 5, the LCSPS 22 includes a fire line mat 30 having the RFID tags 26 embedded in a grid system at known, pre-determined distances with respect to the fire line mat 30. The RFID tags 26 are distributed in the fire line mat 30 according to the amount of error that can be tolerated in a particular system. That is, the more RFID tags 26 that are used in a fire line mat 30, the more accurate the measurement of the RFID reader 28 of the position of the user 6.

RFID tags 26 require no external power source; rather, the power is generated by the radio frequency energy that is transmitted to each RFID tag 26. The identification of each RFID tag 26 is the distance from a reference tag. The RFID reader 28 can have sensing distance of about six feet. Therefore, the RFID reader 28 can read any RFID tag 26 within its range to determine the actual position of the simulated weapon 10 and student along the firing line mat 30. The RFID reader 28 can be located in or proximate the simulated weapon 10, and the RFID reader 28 communicates with the weapon controller card 24 of the simulated weapon 10. The weapon controller card 24 is in communication with the central simulation computer 15 (via either a wireless or wired connection 23), and transmits the position of the simulated weapon 10 to the central simulation computer 15 as part of the firing packet of the simulated weapon 10 so that the central simulation computer 15 can use this information and the data from the ELPS 20 to compensate for the error caused by physical misalignment of the sight 27 and laser line 16. This method of sensing the position of the simulated weapon 10 will continuously monitor the position of the student to allow the student to move around during a simulation exercise.

Alternatively, if the simulation does not require the students to move from a single location, then each student's position can be entered into the simulation computer 15 by the instructor at the beginning of an exercise. In this way, the use of an LCSPS 22 or any other position sensing technology is not necessary and only the ELPS 20 is used to compensate the misalignment error.

Having thus described exemplary embodiments, it should be noted by those skilled in the art that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifications may be made within the scope of this disclosure as described herein and as described in the appended claims. 

1. In a weapon simulation system, a method for correcting misalignment error between a laser of a simulated weapon and an actual aim point line of the simulated weapon to correct for residual misalignment error that remains after all mechanical adjustments have been made to the simulated weapon, said method comprising the steps of: a) storing a compensation offset profile and a compensation angle profile for the simulated weapon in a weapon controller card in the simulated weapon; b) transmitting said compensation offset profile and said compensation angle profile from said weapon controller card to a central computer; c) calculating the misalignment error of an aim point on a screen of the aim point line by said central computer using said compensation offset profile and said compensation angle profile from said weapon controller card; and d) identifying the actual aim point in the central computer by using the misalignment error.
 2. The method as described in claim 1, wherein prior to step a) further comprising: measuring at a known reference plane a compensation angle between the aim point line corresponding to the position of the simulated weapon and a laser path generated by a laser module in the simulated weapon to generate a compensation angle profile.
 3. The method as described in claim 1, wherein prior to step a) further comprising: measuring at a known reference plane a compensation offset between the aim point line corresponding to the position of the simulated weapon and a laser path generated by a laser module in the simulated weapon to generate a compensation offset profile.
 4. The method as described in claim 1, prior to step c), further comprising the step of: determining position information of the location of the simulated weapon with respect to a screen of the weapon simulation system using an RFID reader and at least one RFID tag positioned in a fire line mat, said RFID reader in electrical communication with said weapon controller card; and transmitting said position information from said weapon controller card to said central computer for calculating the misalignment error of the aim point on the screen.
 5. The method as described in claim 4, further comprising the steps of: connecting an RFID reader with the simulated weapon, said RFID reader in electrical communication with said weapon controller card.
 6. The method as described in claim 1, wherein prior to step c), further comprising: measuring the cant angle position of the simulated weapon with a cant sensor in electrical communication with said weapon controller card; and transmitting said cant angle position from said weapon controller card to said central computer to compensate the position of aim point.
 7. A weapon simulation system minimizing laser misalignment error, said weapon simulation system comprising: a central computer controlling a weapon simulation; a first simulated weapon having a laser module and a sight; and a weapon controller card connected with the first simulated weapon and in electrical communication with said central computer, said weapon controller card storing a compensation offset profile and a compensation angle profile exclusively for said first simulated weapon to correct for residual misalignment error that remains after all mechanical adjustments have been made to the simulated weapon.
 8. The system as described in claim 7 further comprising a cant sensor housed in the first simulated weapon, said cant sensor in electrical communication with said weapon controller card to transmit a cant angle to said weapon controller card.
 9. The system as described in claim 7 further comprising: a fire line mat having at least one RFID tag positioned therein; and a RFID reader in electrical communication with said weapon controller card, said RFID reader connected to the simulated weapon to identify the location of said first simulated weapon when said RFID reader detects said RFID tag, said weapon controller card transmitting said compensation offsets and angle profile and said location information to said central computer.
 10. A weapon simulation system minimizing laser misalignment error, said weapon simulation system comprising: computer means for controlling a weapon simulation; a simulated weapon having an associated laser module and a sight; and an individual weapon controller card connected with said simulated weapon of said system and in electrical communication with said computer means, said weapon controller card storing a compensation offset profile and a compensation angle profile only for the associated simulated weapon to correct for residual misalignment error that remains after all mechanical adjustments have been made to the simulated weapon. 